The present invention relates to the precision mounting and location of a micro switch for actuation repeatedly where it is necessary to have the actuation occur at the same point in the relative movement of the device actuating the microswitch. This requirement arises typically in the mounting of a microswitch for actuation by a pressure- or temperature-responsive sensing mechanism which provides movement of an actuator member proportional to a change in pressure or temperature over the desired range to be monitored. Examples of this type of mechanism employing a microswitch are appliance thermostats and pressure switches. Typically the microswitch is mounted on a mounting bracket having a temperature- or pressure-responsive sensing assembly connected thereto. The mechanism of the sensor is typically calibrated with respect to the position of the microswitch actuator for providing switch actuation and deactuation at the desired point in the sensing range of the temperature or pressure sensor.
Heretofore, in the design and manufacture of thermostats and pressure switches employing a microswitch, it has been found that over a period of time in field service, the devices lose calibration because of movement of the microswitch on its mounting with respect to the sensor mechanism for effecting actuation of the microswitch.
Typically, microswitches have apertures provided in the body thereof for receiving therethrough screws which threadedly engage the mounting structure. One common technique for mounting a microswitch is to employ a generally U-shaped bracket with the microswitch clamped between the opposite sides of the bracket by threaded engagement of the screw with the bracket. However, the clearance between the mounting screw and the mounting apertures provided in the microswitch body permit movement of the switch unless sufficient friction is provided between the sides of the mounting bracket and the surfaces of the microswitch. It has been found that in extended field service, any relaxation of the friction forces due to aging of the components or vibration, permits the forces of switch actuation to move the microswitch body with respect to the bracket and change the calibration of the pressure or temperature sensing mechanism. Thus it has long been desired to find a way or means of mounting the microswitch in such a manner that the microswitch will maintain its position on the mounting for enabling precise and repeatable actuation by a sensing mechanism.